To the authors' knowledge, this study presents the first γ–aminobutyric acid (GABA) concentration measurements in unmedicated patients with schizophrenia, who showed elevations in both GABA and glutamate–glutamine (Glx) levels in the medial prefrontal cortex but not the dorsolateral prefrontal cortex. Medicated patients did not show these elevations, suggesting possible normalization of levels with antipsychotic medication. The Glx elevations agree with prior magnetic resonance spectroscopy literature, but GABA elevations were unexpected and suggest possible involvement of classes of interneurons not found to show impairments in postmortem studies.